gdgt

It does slow down towards the end of the charge still, that's true. It just doesn't seem coincidental that I'd suddenly see an improvement in battery life, but perhaps I should test the theory.

It is possible that there is some sort of secret that iMacs (and presumably other Apple computers) are aware of that makes a difference when it is charging an iOS device, but I wouldn't think so. I would think that you would get the same result charging from a 500ma source as you would from any Apple Computer, and you should get the same result charging from any 1000ma source as the iPhone charger. The real question is, Do you get the same resulting battery life no matter what the maximum ma the charger provides, and is the Mac some how special? Thoroughly testing this theory is not a simple task. I also think it is possible that the amount of time the phone is connected to the charger could be a factor.

Consider this: If the iPhone is fully charged within 2 hours on the iPhone charger, and then stops charging for the rest of the night, there could be 6 hours of draining from that point forward if the iPhone is drawing charge from the battery (this does not seem likely, as it seems like the iPhone stop drawing power from the battery when connected to a power supply, but I am not certain)

Now consider that the iPhone is charging from a 500ma source and takes 4 hours to fully charge, and only has 4 hours of draining from the battery through the rest of the night, this is a possible explanation of the longer battery life, but I am not sure if it is the case or not.